Mechanization of document handling and counting activities is a field which has developed to a vary considerable degree. Apparatus is presently available to handle count and stack sheets, such as paper currency, checks, food stamps, and the like, at relatively high speeds. One typical apparatus is described in U.S. Pat. No. 3,771,783. This mechanized apparatus typically utilizes cooperating feed and stripper means forming a nip through which sheets pass, the feed and stripper means cooperating to assure the feeding of sheets in single-file fashion toward an out feed location. Acceleration means positioned a spaced distance downstream of the cooperating feed and stripper means provides an acceleration nip through which sheets pass. The purpose of abruptly accelerating sheets is to form gaps between adjacent sheets, which gaps are useful for counting the sheets.
The arrangement shown in aforesaid U.S. Pat. No. 3,771,783, issued Nov. 13, 1973, in which the acceleration nip is separated from the feed and stripper nip, but with no positive drive means being provided therebetween, creates the disadvantage that curled or damaged sheets may undergo additional curling or creasing in this "free-fall" region, lead to the development of the document handling and counting apparatus described in Application Ser. No. 288,646, filed in the U.S. Patent Office on July 30, 1981, and assigned to the assignee of the present invention, now U.S. Pat. No. 4,474,365, which discloses feed rollers mounted on a common axis with an acceleration idler, cooperating with an acceleration roller, forming an acceleration nip with the acceleration idler to abruptly accelerate sheets as they pass through the acceleration nip, whereby sheets moving between the nip formed by the feed roller and stripper assemblies and the acceleration nip are always positively driven by the feed rollers moving toward the acceleration nip to prevent the type of damage which might occur in the apparatus described in U.S. Pat. No. 3,771,783 from occuring through the use of apparatus described in application Ser. No. 288,646, now U.S. Pat. No. 4,474,365, issued Oct. 2, 1984.
The present invention is an improvement upon the apparatus of Application Ser. No. 288,646, now U.S. Pat. No. 4,474,365, issued Oct. 2, 1984, in which sheets having lengths varying over a significantly larger dimensional range are accommodated without the necessity for increasing the size of the feed roller, and in which positive drive is provided for sheets moving between the nip formed by the feed rollers and stripper assemblies and the acceleration nips formed between the acceleration roller and acceleration idler, said positive drive imparting some pre-acceleration to sheets prior to their arrival at the acceleration nips.